The present invention relates in general to an apparatus and method for fabricating structural components. More particularly, this invention concerns an apparatus and method for assembling pre-cut members into trusses and joists.
Prefabricated building components, now widely utilized in the construction industry, are typically assembled at a manufacturing facility and then transported to the job site for incorporation into a building structure. Prefabricated trusses for,use as roof or floor supports are assembled from pre-cut wooden chord and web members positioned in abutting relationship and connected together using toothed fastener plates.
Truss assembly devices have been developed for performing this task semi-automatically. The pre-cut wooden members are positioned manually over a support surface and clamped in place, after which connector plates are laid over the abutting joints. The connector plates are then embedded into the members with a gantry or other press to secure the joints on one side. The semi-complete truss is then turned over and similarly secured at the joints on the opposite side.
Various arrangements or truss tables in gantry presses have been employed in the truss assembly devices of the prior art. The prior truss assembly devices, however, have several shortcomings. The clamping methods utilized by the prior machines have been found inadequate in terms of adjustability, positive actuation and the like. In addition, the prior machines have been relatively slow in operation because movement of the trusses on the table during fabrication has been done primarily manually.
There exists a need for a new and improved truss assembly apparatus.
The invention is for a truss assembly apparatus and a method for assembling a truss utilizing the apparatus. The apparatus comprises a truss table having a work surface divided into a first and second assembly zone. The apparatus further includes first and second clamping assemblies for clamping the truss in the first and second assembly zones. The apparatus includes a flip-over assembly having a flip-over arm movable relative to the truss table for moving the truss from a first truss position in the first assembly zone, wherein a first truss face contacts the work surface, to a second truss position in the second assembly zone, wherein a second truss face contacts the work surface.
The flip-over arm is movable between a home position adjacent said work surface and an extended position, wherein the flip-over arm may be perpendicular to the work surface. In another alternative, at least a portion of the flip-over arm may extend over the second assembly zone when the flip-over arm is in the extended position. The flip-over assembly may comprise a plurality of movable flip-over arms for moving the truss from the first truss position to the second truss position.
The invention preferably includes a lift-out assembly having at least one lift-out arm movable relative to the truss table for moving the truss from the second truss position in the second assembly zone to a finished position spaced from the work surface. The finished position may be above and preferably extends beyond the work surface. The lift-out arm may comprise a plurality of lift-out arm rollers mounted thereon.
The work surface preferably has a plurality of assembly slots therein. The plurality of flip-over arms are aligned with the plurality of assembly slots to allow movement of the flip-over arms from home positions to extended positions. Similarly, the plurality of lift-out arms are aligned with the plurality of assembly slots to allow movement of the lift-out arms.
Flip-over actuators corresponding to the flip-over arms are positioned below the work surface and are interconnected between the truss table and the flip-over arms and are operable to move the flip-over arms. Similarly, the apparatus may include lift-out actuators.
Preferably, the first clamping assembly has a plurality of longitudinally spaced first moveable rails, spaces between the plurality of first moveable rails being aligned with the assembly slots. Similarly, the second clamping assembly preferably has a plurality of longitudinally spaced second moveable rails, spaces between the plurality of second moveable rails being aligned with the assembly slots. The first movable rails are each movable between a first rail home position, wherein the truss is free to move, and a first rail clamped position, wherein the first movable rails contact the truss when the truss is in the first truss position, and wherein the second movable rails are each movable between a second rail home position, wherein the truss is free to move, and a second rail clamped position, wherein the second movable rails contact the truss when the truss is in the second truss position. The first movable rails and the second movable rails are preferably adjacent when the first and second movable rails are in the first and second rail home positions.